This invention relates generally to the field of conjugated polymers, and more particularly relates to a novel class of conjugated polymers useful as semiconductive materials in electroluminescent devices and the like.
xe2x80x9cConjugatedxe2x80x9d polymers are polymers having a xcfx80-electron conjugated system along the main chain (or xe2x80x9cbackbonexe2x80x9d), and have been known for some time to have utility as organic semiconducting materials. See, e.g., Organic Conductors, ch. 11, J.P. Farger, Ed. (New York, N.Y.: Marcel Dekker, 1994). Conjugated polymers include, for example, cis and trans polyacetylenes, polydiacetylenes, polyparaphenylenes, polypyrroles, polythiophenes, polybithiophenes, polyisothianaphthene, polyphenylenevinylenes, polythienylvinylenes, polyphenylenesulfide, and polyaniline. More recently, conjugated polymers have also been discovered to be useful as electroluminescent materials, i.e., as materials that emit light when excited by application of an electric current (Burroughs et al. (1990) Nature 347:539-541; May (1995) Phys. World 8(3):52-57). Accordingly, these polymers have been proposed for use in a variety of applications. For example, conjugated polymers may be used as the active material in semiconductor thin film devices such as light emitting diodes (LEDs), transistors, photodetectors and solar cells. Conjugated polymers may also be used in electrochemical devices such as rechargeable batteries and light emitting electrochemical cells (both as thin films and in solution), as electrochemical sensors, and as electrical conductors (after being heavily doped).
Poly(p-phenylene vinylene) (xe2x80x9cPPVxe2x80x9d) is a conjugated polymer of particular interest because of its simplicity and cost; the polymer is also advantageous in terms of processability and tensile properties; see Kraft et al. (1998) Angew. Chem. Int. Ed. 37:402-428. 
Like other conjugated polymers, PPV is insoluble in most organic solvents, including those used in silicon microfabrication technology. Some soluble PPV derivatives have been prepared by covalent attachment of flexible side groups or segments; such derivatives include poly (2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene (xe2x80x9cMEH-PPVxe2x80x9d) (see U.S. Pat. No. 5,189,136 to Wudl et al.) and poly (2,5-bischelostanoxy-1,4-phenylene vinylene) (xe2x80x9cBCHA-PPVxe2x80x9d) (e.g., as described in International Patent Publication No. WO 98/27136), which are soluble in common solvents such as toluene, tetrahydrofuran, xylene and chloroform. However, these side groups are electronically passivative, and considerably reduce the semiconductivity of the conjugated polymer by separating polymer chains from each other and consequently hindering charge mobility between polymer chains. U.S. Pat. No. 5,604,292 to Stenger-Smith et al. is also of interest insofar as the patent pertains to a PPV derivative, i.e., poly(2-N,N-dimethylamino phenylene vinylene), but that polymer as well is limited in terms of electroluminescence.
There is accordingly a need in the art for conjugated semiconductive polymers that are soluble in common organic solvents, particularly those used in semiconductor processing, but nevertheless retain semiconductivity, photoluminescent and electroluminescent efficiency, tensile strength, and thermal, chemical and photochemical stability.
The present invention is addressed to the aforementioned need in the art, and provides a novel family of conjugated semiconductive polymers useful in a variety of applications, including fabrication of semiconductor thin film devices (e.g., LEDs, transistors, photodetectors and solar cells) and electrochemical devices (e.g., rechargeable batteries, light-emitting electrochemical cells, and electrochemical sensors).
It is another object of the invention to provide such conjugated semiconductive polymers in the form of poly(arylene vinylenes) wherein some or all of the backbone arylene units are substituted with an arylamine functionality.
It is still another object of the invention to provide such conjugated semiconductive polymers wherein the substituted poly(arylene vinylene) is poly(P-phenylene vinylene) or a derivative or analog thereof.
It is yet another object of the invention to provide an arylamine-substituted monomer useful for preparing the aforementioned conjugated polymers.
It is an additional object of the invention to provide electroluminescence devices containing a polymer of the invention as the electroluminescent material.
It is a further object of the invention to provide other types of semiconductor thin film devices and electrochemical devices fabricated with a polymer of the invention.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention.
In one embodiment, then, new conjugated polymers are provided in the form of arylamine-substituted poly(arylene vinylenes) containing monomer units having the general structure of formula (I) 
wherein: Ar is arylene, heteroarylene, substituted arylene or substituted heteroarylene containing one to three aromatic rings; R1 is an arylamine substituent having the formula xe2x80x94Ar1xe2x80x94N(R4R5) wherein Ar1 is as defined for Ar and R4 and R5 are independently hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, or substituted heteroatom-containing hydrocarbyl, or R4 and R5 can together form a cyclic group; and R2 and R3 are independently selected from the group consisting of hydrido, halo and cyano, or may be as defined for R4 and R5, or may together form a triple bond.
In another embodiment, novel monomers are provided that are useful for synthesizing the aforementioned polymers, the monomers having the general structure (VI) 
wherein: Ar and R1 are as defined previously, and L1 and L2 are selected from the group consisting of xe2x80x94CHO, xe2x80x94Br, xe2x80x94I and xe2x80x94CH2xe2x80x94L wherein L is a reactive group (e.g., a leaving group) that enables reaction with like monomers (i.e., also having the structure of formula (VI)) and/or with vinyl monomers.
In a further embodiment, electroluminescence devices are provided that contain a polymer of the invention as the electroluminescent materials. These devices include light-emitting diodes (LEDs), photodetector devices, and light-emitting electrochemical cells. In a particularly preferred embodiment, an electroluminescence device prepared with a polymer of the invention is a cavity-emission electroluminescence device.
In an additional embodiment, other types of devices are provided that are fabricated with a polymer of the invention, particularly photovoltaic devices used for the generation of electrical power, electrochemical sensors used for detecting and/or quantitating chemical and/or biological materials, and transistors, e.g., field-effect transistors (FETs).